Responding to PAR-01-089 for Advanced Centers for Interventions and Services Research (ACISR), the Duke Clinical Research Institute (DCRI) in concert with the American Academy of Child and Adolescent Psychiatry (AACAP) propose to develop an innovative large, simple "pragmatic" trials network, the Child and Adolescent Psychiatry Trials Network (CAPTN). The overall goal of CAPTN is to provide reliable estimates of mental health outcomes applicable to a broad patient base treated under usual clinical conditions without bias. Guided by CAPTN participants and a Steering Committee representing the major stakeholders in the field, we take as our starting place two critically important clinical issues: (1) widely used single and combined drug treatments for which randomized evidence is absent and (2) the long-term safety of mono and polypharmacy. CAPTN will operate as a Center within the DCRI, an experienced academic research organization with extensive experience in clinical trials coordination. Four Cores are proposed: The Operations Core provides overall administrative leadership, project management, site management, data management, and statistical services, as well as administrative oversight of the career development and clinical research training program. The Methods Core selects the questions to be addressed and provides expertise in research design, clinical trial methodology, practice research, clinical assessment, bioinformatics, and data analytic techniques. The Trials Core focuses on the development of specific trials to be conducted by the Network. Working with the AACAP, the Network Core provides for the development and expansion of the network. With 200 to 400 child and adolescent psychiatrists each participating in two to four randomized controlled trials per year, CAPTN enacts recommendations of the Clinical Treatment and Services Research Workgroup of the National Advisory Mental Health Council (NAMHC) to develop "strategies for increasing the relevance, speeding the development, and facilitating the utilization of research-based treatment and service interventions for mental illnesses into both routine clinical practice and policies guiding our local and national mental health service systems."